Sight system for firearms



A. L. EVERITT SIGHT SYSTEM FOR FIREARMS Feb. 3, 1959 3 Sheets-Sheet 2 Filed July 12, 1956 INVENTOR. ALLEN LEVER/T7 ATTORNEY Feb. 3, 1959 A. L. EVERITT 2,871,566

SIGHT SYSTEM FOR FIREARMS Filed July 12, 1956 5 Sheets-Sheet 3 10i INVENTOR.

y ALLEN L. EVEEITT A TT'OR NE Y United States Patent sronr SYSTEM FOR FIREARMS Allen L. Everitt, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application July 12, 1956, Serial No. 597,466

Claims. (CI. 3358) This invention pertains to firearms, and more particularly to a firearm sighting system including front and rear sights.

Firearms that are subjected to sustained and rapid firing occasionally require barrel replacement or interchange. Thus, it is common practice to carry interchangeable spare barrels for a firearm, such as a light machine gun. Heretofore, when a barrel was replaced, the rear sight had to be recalibrated, or zeroed in. Inasmuch as this operation cannot be readily accomplished in the field, replacement or interchange of barrels usually adversely affected the accuracy of the firearm.

In addition, it is known that a heavy gun barrel will warp, or droop, when the firearm is fired from the shoulder or a tripod wherein the muzzle is unsupported. However, the barrel will deflect appreciably when it is fired with the muzzle supported by means of a bipod. The sight system of this invention includes adjustable front and rear sights wherein the rear sight is zeroed for elevation and windage to the gun and the front sight is zeroed in to the rear sight upon replacement of the barrel. In addition, the rear sight is designed to compensate for firing of the gun with the muzzle supported or unsupported. Accordingly, among the objects of this invention are the provision of a front and rear sight system for firearms; the further provision of a rear sight having independent means for elevation zeroing and elevation adjustment so as to compensate for firing of the gun with the muzzle supported or unsupported; the further provision of an adjustable front sight to compensate for interchange of barrels; and the still further provision of a self-holding spring base for a gun sight.

The aforementioned and other objects are accomplished in the present invention by incorporating independently adjustable front and rear sights. Specifically, the rear sight may be adjusted for windage and elevation zeroing, and once these adjustments have been made, the rear sight is calibrated to the firearm and to the original equipment barrel. Thereafter, the rear sight may be adjusted for elevation, or range, only. The front sight is carried by the barrel and may be adjusted to the rear sight for both windage and elevation, for subsequently interchanged spare barrels.

The rear sight includes a generally U-shaped spring base, the bottom and legs of which are slotted. The bottom is dove-tailed in cross section and is slidably received in a transversely extending dove-tailed groove in the receiver portion of the firearm. The use of a spring base obviates the necessity of critical fits since the legs of the base are resiliently urged into frictional engagement with the slotted receiver portion. The base may be adjusted transversely of the receiver portion for windage zeroing after which it is staked in place if necessary or desired. A rear sight post is pivotally connected to the upstanding legs of the base, a spring being interposed between the bottom of the base and the post. The rear sight post has an opening which receives one end of a threaded stud. The other end of the threaded stud is 2,871,566 Patented Feb. 3, 1959 attached to a sighting member formed with grooved edges that are received in tongue portions of a frame. A nut threadedly engages the stud, the nut being restrained against axial movement whereby rotation thereof will effect vertical movement of the stud and sighting member, as controlled for positioning by ball clicks.

The frame is generally U-shaped, the ends of the legs being rigidly attached to the sight post. Each leg has a pair of spaced, threaded openings arranged to receive screws for adjustably securing spring loaded scale members thereto. One scale member is used for elevation adjustment when the muzzle is supported and the other scale is used when the muzzle is unsupported. Each scale is independently adjustable for vertical zeroing by loosening the screws and moving the scale vertically in either direction.

The front sight comprises a base that is fixedly attached to the barrel. The base includes a bifurcated portion having a threaded opening. The upper end of the base is formed with a transversely extending, T-shaped groove therein within which a slide is disposed. The slide is also bifurcated and includes a threaded opening for receiving a front sight post. The front sight post may be adjusted for windage and elevation, and after the adjustments have been made, the front sight post is retained in position by means of a screw which draws the bifurcated portions of the base and slide together. Only the front sight is adjusted when the gun barrel is replaced by spare barrels, since the rear sight is initially zeroed in to the firearm during manufacture thereof.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Figure l is a view, in elevation, of a firearm embodying the sight system of this invention;

Figure 2 is a fragmentary view, in elevation, of the rear sight;

Figure 3 is a sectional view taken along the line 33 of Figure 2;

Figure 4 is a perspective view of the rear sight base;

Figure 5 is a perspective view of the rear sight spring;

Figure 6 is a perspective view of a rear sight scale;

Figure 7 is an elevation of another embodiment of the rear sight;

Figure 8 is a cross section along the line 8--8 of Figure 7;

Figure 9 is a view, in elevation, of the front sight, the barrel being shown in section;

Figure 10 is a sectional view taken along the line 9-9 of Figure 9; and

Figure 11 is a perspective view of the front sight bifurcated portion.

In the embodiment shown in Figures 1-8, a firearm 30 has a rear sight receiver portion 31 and a barrel 32. An adjustable rear sight 33 is attached to the receiver portion 31. A front sight 34 is attached to the barrel 32.

A U-shaped spring base 35, Figure 4, has a bottom 36 with tapered edges 37 which form a dove-tailing portion. The base has upstanding legs 38 and 39. The bottom 36 and legs 38 and 39 are slotted, as shown at 40, terminating in circular openings 41 and 42. These openings serve as part of a hinge connection for the rear sight, as will become apparent.

The dove-tailed bottom 36 is received in a transverse groove 43 formed in the receiver portion 31. The spoor 43 has tapered, dove-tail receiving sides 44 which receive the tapered, dove-tail edges 37 of the base 35. The base 35 is made of spring material and the split bottom 36 is slightly compressed within the groove 43 to exert lateral forces to maintain the base member securely in place within the receiver portion 31. This eliminates the necessity of critical fits at this point. If desired, after lateral zeroing of the rearsight within the groove 43, the rear sight may be locked in place by deforming portions of the groove 43 as indicated at 48.

The rear sight 33 includes a sight or elevation post 50, part of which is disposed between the legs 38 and 39 (Fig. 2) and is pivotally connected by a pin 51, passing through openings 41 and 42 of the legs 38 and 39 and through an opening 52 in the post 50.

A spring 53, shown in perspective in Figure 6, is placed between the bottom surface 54 (Fig. 3) of the post 50 and the bottom 36 of the base 35. The spring 53 has a pair of tongues 55, received in slot of the bottom 36 of the base 35. The spring 53 resiliently maintains the sight post 50 in any of a plurality of positions, such as generally perpendicular; or parallel to the axis of the gun barrel 32. For this purpose, the post has faces 56, 57 and 58 which cooperate with the upper fiat portion 59 of the spring 53 to establish these three positions. In addition the post 50 has a foot or stop 60, which abuts the bottom 36 of the base 35 when the post 50 is in perpendicular position. The foot or stop 6!) serves to absorb the recoil inertia forces, and to maintain an accurate perpendicular position of the rear sight.

The sight post 50 is also formed with an opening 61 arranged to receive one end of a threaded stud 62. The other end of the threaded stud 62 is connected by means of a rivet 63 to a sighting member 64. The sighting member 64 is formed with an aperture 65 constituting a peep sight and a V-shaped groove 66 constituting a V- sight. The side edges of the sighting member 64 are formed with vertically extending grooves 67 which receive tongue portions 68 and 69 formed on the inner surfaces of the legs 70 and 71 of a U-shaped frame member 72. The legs 70 and 71 of the frame member 72 are riveted to the post 50. as indicated by numerals 73 and 74, respectively. A pair of strap members 75 and 76 are connected across the legs 70 and 71 by rivets 77 and 78. A nut 79 threadedly engages the stud 62 and is confined between the straps 75 and 76 and the upper edge 77a of the post 50, as shown in Figure 3. The lower edge surface of the nut 79 may be formed with a plurality of radial serrations 80 adapted to receive a pair of balls 81 and 82, which are urged into contact therewith by a pair of springs 83 and 84 disposed in recesses in the post 50.

Inasmuch as the nut 79 is restrained against axial movement relative to the frame 72 and the stud 62, rotation of the nut 79 will effect vertical movement of the stud 62 and the sighting member 64, as viewed in Figures 2 and 3. The spring pressed balls 81 and 82, which engage the radial serrations 80 in the nut 79 act as detents to retain the nut 79 in its adjusted position.

One side of the sighting member 64 is marked bipod, as indicated in Figure 2. This side of the sighting member 43 is formed with an indexing mark 85 to be used with the'peep sight 65. The other side of the sighting member 64 is, likewise, formed with an indexing mark 86 which is used for elevation adjustment when the gun is fired with the muzzle unsupported.

One of the features of the present invention resides in the fact that separate elevation scales are provided for firing the gun with the muzzle supported or unsupported to compensate for barrel deflection which occurs when the muzzle is supported. Thus, leg 70 of the frame 72 is formed with a pair of threaded openings which are arranged to receive screws 87 and 88 for fixedly securing a graduated scale member 89 to the leg 70, which scale is used when the gun is fired with the muzzle supported. Similarly, the leg 71 is formed with a pair of threaded openings arranged to receive screws 90 and 91 for fixedly securing a second scale member 89 to the leg 71, which scale member is used for elevation adjustment when the gun is fired with the muzzle unsupported. The scale members 89, as depicted in Figure 6, comprise bowed self locking spring members having elongated openings 92 and 93. The graduated markings on the scale mem ber 89 are formed on the concave surface thereof so that when the scale members are attached to the frame 72, the stress imposed thereon by the attaching screws will tend to maintain the scale member 89 in fixed position relative to the frame 72.

Vertical zeroing of the rear sight for elevation with the muzzle supported and unsupported is accomplished independently by adjusting the positions of the scales 89 relative to the legs 70 and 71. Once the rear sight 33 has been vertically zeroed with the muzzle supported and unsupported, elevation adjustment is effected by rotation of the nut 79, the left-hand scale 89 being used when the muzzle is unsupported and the right-hand scale 89 being used when the muzzle is supported.

With particular reference to Figures 9, 10 and ll, the adjustable front sight 34 of this invention comprises a base member 100, which is fixedly secured to the barrel 32 by means of a pair of pins 101 and 102. The base includes an upstanding bifurcated portion 103, the upper portion of which is formed with a T-shaped groove 104. One leg 105 of the bifurcated portion 103 is formed with a threaded opening 106 in alignment with a countersunk opening 107 in the other leg 103 of the bifurcated portion. A bifurcated slide member 108 is received in the T-shaped groove 104 of the base 100 and is arranged for transverse movement relative thereto. The sliding member 108 is formed with a centrally disposed threaded opening 109 arranged to receive a front sight post 110. The front sight post 110 may be adjusted for elevation by rotating the post 110 relative to the slide 108. In addition, the front sight post 110 may be adjusted for windage by moving the slide 108 transversely relative to the base 100. After the windage and elevation adjustments of the front sight have been completed, the post is fixedly secured to the'base 10.0 by means of a screw 111 which threadedly engages the opening 106 and extends through the opening 107 so as to draw the bifurcated portion 103 of the base 100 and the bifurcated slide 108 together.

In use of the embodiment of Figures l-6 and 9-11, the rear sight 33 is zeroed for windage and elevation after being attached to the receiver portion 31 of a firearm having a barrel 32 attached thereto. Windage zeroing is effected by sliding the base 35 transverselywith respect to the receiver portion 31 after which it may be staked in place as indicated at 48 in Figure 2. Zeroing of the rear sight for elevation with the muzzle supported on a bipod is effected by loosening screws 87 and 88 and adjusting the vertical position of the right-hand scale 89 on the leg 70. Similarly, zeroing of the sight in elevation for firing with the muzzle unsupported is accomplished by loosening screws 90 and 91 and adjusting the position of the left-hand scale 89 relative to the leg 71. If after sustained firing of the gun, it becomes necessary to replace the barrel 32, the zeroing adjustments of the rear sight are not altered. When a new barrel is attached, the adjustable front sight is calibrated to the rear sight 33 by adjusting the front sight post 110 both transversely and vertically relative to the front sight base 100. Inasmuch as this adjustment may readily [be made in the field, it is apparent that the improved sighting system of this invention greatly facilitates replacement or interchange of gun barrels without sacrificing the accuracy of the firearm.

In the embodiment showing Figures 7 and 8, the parts [below the upper edge 77a of the, post 50 may be identical with the similar parts with the same reference numerals previously described with respect to Figures 1-6 and 9-11. The rear sight of Figures 7 and 8 may be used with the front sight 34 previously described. The bottom surface of nut 79a may have radial serrations similar to 80, previously described. The threader stud 62 of Figures 7 and 8 cooperates with nut 79a and carries sighting member 64a by rivet 63 also substantially as previously described. In fact, all of the parts of Figures 7 and 8 may be identical with the parts of Figures 1-6, with the exception that a lateral or windage adjustment 120, 121 has been added to the sighting member 64 of previous Figures 1-6. This adjustment may be used with a single sighting notch 66a and a single vertical scale 89, shown in Figures 7 and 8 or with the double sight 65 and 66 and double scale construction shown in Figures 2-7.

The lateral or windage adjustment comprises the laterally adjustable plate 120, provided with the sight notch 66a (and, if desired with the peep hole 65 of Figures 1-6). The plate 120 rests on a horizontal ledge 122 on the sighting member 64a, and has a horizontally extendslot 123. A screw 121 is threaded into threader hole 124 and is used to lock and release the plate 120 for lateral adjustment. The plate 120 is of less lateral extent than sighting member 64a to allow the desired adjustment. The sight plate 120 is adjusted to compensate for drift, and cooperates with either the single scale 89 as shown in Figure 7 or both scales as shown in the embodiment of Figure 2.

If desired, the construction of nut 79a may be different from that of nut 79, although it may be the same in so far as the lateral sight adjustment is concerned, and such construction of nut 79a may be applied to Figures l-7. The nut 79a has two flanges 130 and 131 which snugly fit on either side of the trap member 75a which is connected across the legs 70a and 71a by rivets 77a and 78a. If desired, another strap member 75a (not shown) may be placed on the other side of the gun sight, similarly to the construction of 75, 76 of Figures 1-6. Thus, the nut 79a is restrained against axial movement relative to the frame, and the sighting member whereby rotation of the nut 79a will effect vertical movement of the stud 62 and the sighting member 64a.

In the operation of the embodiment of Figures 7 and 8, all of the operations heretofore described with respect to Figures 1-6 and 9-11 may be repeated. In addition, the rear sight of Figures 7 and 8 may be adjusted laterally by loosening the screw 121 and sliding the plate laterally in the direction and for the distance found to be necessary for windage adjustment. Thereafter the screw 121 may be tightened to lock the plate 120 in correct position.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, as may come within the scope of the claims which follow.

What is claimed is as follows:

1. A sight for a firearm having a receiver portion including, a base slidable transversely of said receiver portion, an elevation post secured to said base, an elevation frame secured to said elevation post, a sighting member slidably engaged with said frame, a graduated elevation scale adjustably secured to said frame comprising a longitudinally bowed spring, and means to effect vertical movement of said sighting member.

2. A sight for a firearm having a receiver portion including, a base slidable transversely of said receiver por tion, an elevation post pivotally secured to said base, means for releasably securing said post in an upright vertical position reiative to said base, an elevation frame secured to said elevation post, a sighting member slidably engaged with said frame, a graduated elevation scale adjustably secured to said frame comprising a longitudinally bowed spring, and means to effect vertical movement of said sighting member.

3. A sight for a firearm having an elevation post pivot ally secured to said firearm, an elevation frame secured to said post, a sighting member slidably engaged with said frame having an index mark, and a graduated scale adjustably secured to said frame to be zeroed with said index mark, said scale comprising a longitudinally bowed spring.

4. A sight for a firearm having an elevation post pivotally secured to said firearm, an elevation frame secured to said post, a sighting member slidably engaged with said frame having an index mark, a graduated scale adjustably secured to said frame to be vertically zeroed with said index mark, said scale comprising a longitudinally bowed spring, and a sight plate laterally adjustable on said sighting member for lateral zeroing of said sight.

5. A sight for a firearm having a receiver portion including, a base attached to said receiver portion, an elevation post secured to said base, an elevation frame secured to said post and having a pair of spaced legs, a graduated elevation scale adjustably secured to each leg of said frame comprising a longitudinally bowed spring, a sighting member slidably engaged with said frame having index marks arranged to coincide with each graduated scale, one scale being used when the muzzle of the firearm is supported and the other scale being used when the muzzle of the firearm is unsupported, and means to effect vertical movement of said sighting member.

References Cited in the file of this patent UNITED STATES PATENTS 447,886 Lyman Mar. 10, 1891 584,629 Dolan June 15, 1897 769,089 Johnson Aug. 30, 1904 888,858 Sutherland May 26, 1908 963,389 Pilblad July 5, 1910 1,326,464 Newitt Dec. 30, 1919 1,358,794 Stewart Nov. 16, 1920 1,491,141 Johnston Apr. 22, 1924 2,192,544 Fisk Mar. 5, 1940 2,208,576 Garand July 23, 1940 2,473,891 Lillard June 21, 1949 OTHER REFERENCES War Dept. Technical Manual: TM 9-1215, Thompson Submachine Gun Cal. 45, M1928A1 March 1, 1942; pages 14, 16 and 22. 

